Method of making turbine wheels



D. P. EASTMAN ET AL METHOD OF MAKING TURBINE WHEELS July 3, 1951 2 Sheets-Sheet 1 Original Filed Jan. 25, 1946 July 3, 1951 D. P. EASTMAN EI'AL METHOD OF MAKING TURBINE WHEELS 2 Sheets-Sheet 2 Original Filed Jan. 25, 1946 I 71 06222025 Ba uzdfliaszwai? Tkeodare .Z. J'zaazfisezz Patented July 3, 1951 2,559,013 METHOD OF MAKING TURBINE WHEELS David P. Eastman, Chicago, Ill., and Theodore L. Swansen, Milwaukee, Wis., .assignors to United Specialties Company, Chicago, Ill., corporation of Delaware Original application January 25, 1946, Serial No. 643,242. Divided and this application January 18, 1947, Serial No. 722,788

3 Claims.

This invention relates to a method of making the buckets of a turbine wheel and to the method of making a turbine wheel. It has for one object to provide a method for forming unitary turbine buckets.

Another object is to provide a method of forming a unitary turbine bucket from a hollow or unitary member.

Another object is to provide a method of making a turbine wheel and of assembling it from buckets made as above indicated.

Other objects will appear from time to time throughout the specification and claims.

The invention is illustrated more or less diagrammatically in the accompanying drawings, wherein:

Figure 1 is an elevation of a blank for one form of bucket;

Figure 2 is an end view of the blank of Fig-- ure 1;

Figure 3 is a side elevation with parts broken away and parts in section, illustrating the bucket after formation;

Figure 4 is a section taken at line 4-4 of Figure 3;.

Figure 5 is a section taken at line 5-5 01' Figure 3;

Figure 6 is a top plan view of the bucket of Figures 3, 4 and 5;

Figure I is a perspective view of a completed bucket;

Figure 8 is an elevation similar to Figure 6, showing a modified form of bucket;

Figure 9 is a section taken at line 9-4 of Figure 8;

Figure 10 is a side view with parts broken away and parts in section, illustrating a turbine wheel to which have been applied the bucketof either of the previous forms; and

Figure 11 is a section on line ll-H of Figure 10.

This application is a division of our co-pending application Serial No. 643,242, filed January 25, 1946.

Like parts are indicated by like symbols throughout the specification and drawings.

The method of making the bucket and the turbine wheel can best be explained by explaining first the construction of the buckets and the ultimate construction of the wheel.

In the particular form here shown the buckets are illustrated as being formed in two manners. As illustrated in the first seven figures, the bucket is formed of tubing. As illustrated in Figures 8 and 9 it is formed of sheet material. The form of the first seven figures will first be described.

A piece of seamless tubing I of suitable length forms the blank for a bucket. Portions are cut away to provide tongs 2 and the tones are curled or bent toward the body of the remaining portion of the tube to form the ears 3. That portion of the tube which is to form the bucket The invention is not limited to the particular contour or shape of bucket shown, and a bucket might be made in many different forms without departing from the spirit of the invention. The bucket is hollow vfrom end to end although this is not essential. Where ventilation or cooling of the bucket is provided, it is advantageous to have the bucket hollow.

In the modified form of Figures 8 .and 9 the bucket has substantially the same contour and shape as that shown in the earlier figures, but instead of being formed of the tube, it is formed of a sheet of material. As formed thereare extensions 6 from the main body of the bucket and the extensions are shaped or bent to provide ears 1. A depression or. trough-like portion 8 is formed in the bucket and along this portion the two edges of the material meet and may be welded, as at 9, or otherwise secured together. A bulge or enlargement I 0 is formed of the material.

In the formation of a turbine wheel a plurality of buckets made according to either of the forms illustrated in the first nine figures is arranged about the periphery of the wheel. The buckets are first arranged about a ring I l which has a reduced portion l2. The portion i2 is so shaped that the buckets fit snugly over it with their bottom portions against the periphery of the reduced portion l2 and their respective ears against the shoulder l3 formed between the portion i2 and the ring I l.

Ring-like members H, which may be of any desired form or shape, are positioned about the ring II and the ears 3 or I are bent over them into the form shown in Figure 11. The ring-like members It may preferably be wires or rods which have been given circular shape and they may be endless if desired, or they need not be.

When the buckets are positioned upon the ring ii the ring itself is positioned between two wheel members. These in the particular form shown constitute a member l5 having an inwardly directed fiange i6 and a member I! having a corresponding inwardly directed fiange I 8. The member I! may be perforated, as at It, for cooling or ventilation, if desired. The two wheel members l5 and I! are preferably secured together in any desired manner. As shown, they are held together by rivets 20. A wheel may be secured to a hub 2| by screws 22, or otherwise. A shaft 23 is secured to the hub 2| in any desired manner.

In the assembly the parts are so proportioned that the flanges I 6 and I8 fit closely against the ears 3 and also fit closely against the portions 2 or 6 of the buckets, so as to press them against the reduced portion l2 of the ring H. The ring H is itself not positively secured to any part of the wheel and is confined solely by the bucket anchors 2, 3 or 6, I, which in turn are confined by flanges l6 and I8 and wheel members It and I1. When the wheel is in use and rotating at high velocity, the ring ll, 12 has a tendency to expand under the influence of centrifugal force. The flanges l6 and 18 also tend to expand under the influence of centrifugal force. However, unlike the ring I I, 12 these flanges are restrained by the solid disc members 15 and I1. The flanges thus expand less than the ring I I, I2 and support a large percentage of the centrifugal load imposed upon the wheel through the buckets 2 and 3 or 6 and I and the ring members It. This tendency results in an increased compression on the ears 3 or I and upon the retaining wire members ll. Thus as rotation increases and centrifugal force which would normally tend to throw the bucket out of the wheel is increased, the ring expands sufficiently to increase the compression on the ears 3 or I of the buckets and thus additionally to hold them in place. Means are thus provided for gripping the buckets more tightly in the wheel at the exact time when the tendency to throw them from the wheel is increased.

Although we have shown an operative form of our invention, it will be recognized that many changes in the form, shape and arrangement of parts can be made without departing from the spirit of the invention, and our showing is therefore to be taken as, in a sense, diagrammatic.

The use and operation of this invention are as follows:

The buckets shown are preferably made of metal, although they might be made of other materials. The choice of material will depend largely upon the use to which the wheel is to be put, the speed at which it is to operate and the propelling fluid with which it is to be used. However, as the buckets are made they are provided with the extensions 2 or 6 and with the ears 3 or I. A suitable number of buckets is then positioned upon a ring, either as shown upon the ring II or upon the ring shown in the later figures. The buckets fit snugly about the reduced portions of the ring and are held in place by the members I4 about which the ears 3 or 'I are bent.

The ring with the ears upon it is then assembled between twowheel members and proportions of the parts are such that the ears are gripped tightly between the shoulders formed at the reduced portion II and the inwardly bent flanges l6 and 18 of the wheel members. When 1 the wheel members are then fastened together, the buckets are additionally held in place.

When the bucket and wheel construction illustrated is embodied in a turbine, propelling fluid is discharged against the buckets and the wheel is revolved. As the wheel revolves rapidly, centrifugal force is developed with increasing speed of rotation and a tendency to throw the buckets outwardly develops. Before this tendency develops to dangerous proportions, the

same centrifugal force is effective upon the ring II and tends to stretch or spread it sufiiciently to cause it to yield outwardly slightly and to exert an added compression upon the ears 3 or I of the buckets. This forces these parts with increasing pressure against the more highly restrained flanges i6 and I8, and therefore the centrifugal force which in one sense tends to throw the buckets away from the wheel, in another sense sets up a condition which additionally and increasingly tends to hold the buckets tighter and tighter as the speed of rotation increases.

The structure and method of this invention comprise not merely a useful bucket and wheel construction but provide a bucket and wheel construction which in itself is, so to speak, self-tightening under conditions of use.

We claim:

1. The method of making a turbine wheel which includes the steps of forming a ring-like member, forming bucket members of suitable contour and providin on said bucket members pairs of ring engaging parts, positioning a plurality of buckets upon said ring with their engaging parts in contact with each other and one on each side of said ring, P sitioning a plurality of annular members in engagement with said ring engagin bucket parts. shaping said engaging parts about said annular members, and finally positioning a pair 'of bucket discs about said ring and in engagement with said ring engaging parts. and securing the several parts together.

2. The method of making a turbine wheel which includes the steps of forming a ring-like member with a pair of oppositely placed shoulders, forming bucket members of suitable contour and providing on said bucket members pairs of ring engaging parts, positioning'a plurality of buckets upon said ring with their engaging parts one on each side of said ring and each against a shoulder, positioning a plurality of armular members in engagement with said ring engaging bucket parts, shaping said engaging parts about said annular members, and finally positioning a pair of bucket discs about said ring and in engagement with said ring engaging parts, and securing the several parts together.

3. The method of making a turbine wheel which includes the steps of forming a ring-like member, forming an outwardly directed pair of shoulders on the opposite edges of said ring-like member, forming a plurality of bucket members of suitable contour and providing on 'each of said bucket members a pair of oppositely placed ring-engaging parts, positioning a plurality of buckets upon said ring with their engaging parts one on each side of said ring, positioning a plurality of annular members in engagement with said ring-engaging parts, shaping said bucket parts about said annular members and in engagement with said shoulders, forming a pair of disc-like members, forming on said disc-like members laterally directed peripheral flanges, positioning one of said disc-like members on each side of said ring, and buckets with said flanges overlying said annular members and the ends of said bucket-engaging parts, and securing said disc-like members together.

DAVID P. EASTMAN. THEODORE L. SWANSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

